Electromagnet-coil construction.



M. J. WOHL & H. HERTZBERG.

ELEUTROMAGNET COIL CONSTRUCTION.

APPLICATION FILED APRZL 1908. I

Patented Aug. 17, 1909.

2 SHEETS-SHEET 1.

M. J. WOHL & H. HERTZBERG. ELECTROMAGNET COIL CONSTRUCTION.

2 SHEETS-SHEET 2.

Patented Aug. 1?, 1909.

5: xxii h .EQLECJQ APPLICATION PILBD'APR.21,1908.

Gm Y nannies LWOHL, OFNEWTYORK, aun naanvnna'rznnne, or BROOKLYN, NEW YORK, ASSIGNORS-TO ABBOT AaLOW, ornonsnsnon; NEW YORK, MAURICE J. WOHL, OF NEW Yonn, N. Y., AND HAR HERTZBERG, OFgB-ROOKLYN, NEW YOR TRUSTEES.

2 ELISeTBOiIAGN r-wmconsrnno'rron.

Specification of Letters Patent.

Patented Au 17, 1909':

Application filed April '21, 1908.. Serial No. 428,401.

To all whom it may concern:

Be it known that we, MAURICE J. WVOHL and HARRY Hnnrznnne, citizens of the United States, and residents, respectively, of the city of New York, borough of Manhattan, county and State of New York, and of thecityof New York, borough of Brooklyn, county of Kings, and State of New York, have invented certain new and useful Improvements in' Electromagnet-Coil Con struction, of which the following is a specification.

' This invention relates to are lamps, and

r i the object of the inventionis to provide certain improved nieans for controlling the movable electrode.

The mvention consists in certain improvements wherein a solenoid and core control the movable electrode, and also in the constructlon of and method of constructing solenoids or coils.

" 1, the bottom plate 2, the intermediate platform 3, and a pair of vertical guide rods 4 -.1; connecting said plates and platform. A

hanger 5 may be connected to but insulated I vfrom the top plate 1.

6 is the up er, movable electrode, which passes througralined apertures in plate 2 and platform 3- and is held at its upper end in a suitable tubular holder 7, which ispin turn, carried by the block 8 mounted shd-,

ably between the rods 9 is the lower, fixed electrode, which is.

held by the bracket 10 depending from the plate 2..

The immediate .instrumentality for controlling the electrode 6 may be a clutch loop 11. However, no novelty is claimed for this clutch loop per 88, nor, indeed, do the features alread recited constitute part of the novelty of t 1epresent invention.

I 12 is an upright" frame support, which may be employed, and w-hich may be secured to said support.

The portion of the circuit within the lamp cured to, but suitably insulated from, the platform 3 This support may carry a coil or solenoid 13, wound on the spool 1'41 se- The support may also have dependin from its upper end a dashpot 15, prefera ly of brass.

Longitudinally movable within the solenoid 13 is an iron core 16, which passes through an aperture 17 in the platform 3.

To the upper. end of-this core may be secured, as yastem 18, a graphite lunger 19, which works within the shell or ashpot plunger need not be en'- 15. 1 Offcourse, the tire. o. a lite. Tl i eloi viir end a weight 30, which also serves as a stop, by engaging the lower surface of the platform 3, to prevent undue upward movement of the core. -The clutch loop member 11 is ,-.pivotally connected to the core 16, very'i c to the weight 30; insulation'-20j.b vided at the pivotal joint.

The current enters atone of twolnnding posts 21, conveniently disposed at the top of the lamp, and passes out at the other.

includes the variable resistance 22, the upper electrode .6, the lower electrode 9, the bracket 10, and the solenoid 13. In operation, as will be readily understood, when the current becomes too weak, owing to the burning away of the electrodes, the mag- V of the core 16 may carry 1;

uetic field of the solenoid is weakened, permitting the core to descend, and the clutch loop 11 to assume a substantially horizontal position, when the clutch'ceases to bite upon the upper electrode and the latter descends.

If the are is too intense, the heavier current passingthrough the solenoid causes the latter to draw the core upward, thus-tilting the clutch loop 11, until the latter bitesu on the upper electrode and finally lifts the atter bodily. During these operations, the dashpot 15 serves to regulate the movement and to guide the core.

The construction of the solenoid 13 is of striking novelty; The .wire 23 of which this solenoid is formed i's' aluminum; and the wire itself is not covered with insulation in the first place, nor is insulation disposed between the superposedturns Of-yWlI'B. Between the. successive'layers or cylinders of the solenoid, however, -is placed an insula'-.

tion, consisting of a composite strip 24, shown portion of-this strip is'the central layer of -mica 25; and the inclosing layers 26 and 27 are both 'of paper, 'or the one of paper and the othercloth. .Even both might be of cloth. No specific novelty is claimed for this com iositestrip, as it is known-in the electrica world; "butits use in the present connection is regarded as entirely new. A solenoid .of coil constructed in this manner has strikingly new properties. Fig. 2 re'pre sent-s the construction of the solenoid; Fig. 3 indicates the condition'of the coil after some use- It should observed, in the first place, that aluminum wire oxidizes readily.

Even before current is sentthrough, the

.wire may begin to' be covered by a layer of aluminum oxid, represented at 28. After current has passed for some time, this coating of aluminum oxid is of suflicient density toafiord a thoroughly satisfactory insulating envelop for. the wire. In addition, the heat developed within the solenoid burns awaythe layers 26 and 27 of the composite strip, leaving the mica 25. This alfords more room within the solenoid, permitting the turns ofwire to separate. some-what, thus enhancing the insulating efiect.

F ig.- 5 indicates the applicability of the invention to. the differential coil type of lamp. In these, asis well known, one solenoid, here designated 13 is in series with the electrodes, while the othersolenoid, here designated 13 is inshunt across the arc. 'lhe two exert opposite pulls upon the core 16. Whenthe arc voltage gets too high, a larger amount of current passes through the shunt coil and in due time the core is drawn down and a predetermined arc is maintained. With the ordinary constructions of coils orsolen'oids, the shunt coil, which is of fine-r wire than the series coil, being designed to carry less current under normal conditions, is liable to burn out or to have its insulation damaged, in event that'the movable electrode is caught and held in an elevated position,,'which results in the continued passage of a large amount of current through the shunt. In orderto obviate this danger, itha s been customary hitherto to provide an auto'matic circuit breaker, which becomes operative when the electrodes are accidentally held'separated. For this type of lamp, the present invention is particularly valuable. In the first; place, aluminum is of lower conductivity than copper; hence the shunt coil need not be of particularly fine wire, which lessens materialy the danger of burning -out. Further, the aluminum oxid affords a most efficient insulation between the superposed turns, particularly when aided by the spaces left between the turns after the solenoid has'been in use, as already,

described; and. the mica between the cylinders or layersis practically a perfect insulator. 4

While the description hitherto has been directed to the preferred form of solenoid or coil, in which the wire used isaluminum, and the insulating envelop is one of naturally formed aluminum oxid, it should be understood that theinvention is not limited in this respectto aluminum wire and aluminum oxid, but comprehends' as well any solenoid-or coil construction in which the wire, of whatever metal or alloy, is naturally or artificially coated with an insulating envelop of oxid. Thus, copper wire may be employed, and coated artificially with oxid.

'What is claimed as new is:

1. A solenoidor "coil adapted for use in an arc lamp, said solenoid being wound with aluminum wire and comprising a plurality of layers, and insulation between said layers consisting of a composite strip, said strip having a central layer of insulating material and outer layers of readily combustible material.

2. A solenoid or coil adapted for use in an arc lamp, saidsolenoid being wound with aluminum wire and comprising a] plurality of layers, together with a composite insulating strip between said layers, said strip comprising a central layer of mica and outer layers'ofreadily combustiblematerial.

' 3. The method of making a solenoid, which consists in winding successive layers of bare aluminum wire, and placing between the layers a composite insulating strip, consisting of a central layer of insulating bustible material.

4:. A solenoid orcoil wound with aluminum wire without artificial insulation between the convoluti'ons, and'having between the cylindrical layers a composite insulate ing strip composed of a.central layer of mica and outer layers of readily combustible material.

5. A solenoid or'coil adapted for use in an arc lamp, said solenoid belng wound with aluminum wire without artificial insulating covering, and with a composite insulating strip between the cylindrical layers, composed of a central layer of micaand outer layers of readlly combustible material.

Signed at Brooklyn, New York, in the county of Kings and State of New York, this 16 day of'April, 1908.

MAURICE J. WOHL. HARRY HERTZBERG.

Witnesses:

Lewis W. HASKINS,

Gno. VVnLLINo Gnmmos.

-1nateri a1 and covering layers of readily com- 

